Light amplification by stimulated emission of radiation (lasers) devices generate narrow beams of light using optical amplification. Emission from lasers can be characterized as either single-mode or multi-mode emission. Single-mode emission generally refers to light generated by a laser having only one or relatively few dominant wavelengths. On the other hand, multi-mode emission generally refers to light generated by a laser having multiple dominant wavelengths. Single-mode emission is often beneficial over multi-mode emission due to reduced noise when used for communication, and simplified optics that can be designed for operation at the dominant wavelength of operation.
Recent advances in diode-pumped solid state laser technology has facilitated development of laser devices, such as micro-chip oscillating lasers (MCOs) often used as the major component in various laser proximity sensors and fuses, space communication systems, solid state laser transmitters, and many other laser systems. The diode pumped micro-chip laser appears to be attractive in these applications because of its enhanced single-mode performance over a relatively broad frequency range. These diode pumped micro-chip lasers exhibit longitudinal modes that are widely separated so that only one or a relatively few number of modes becomes the functional oscillating mode. Besides all other requirements, the micro-chip based oscillator and its laser transmitter must provide precise and reliable single mode operations. A proper packaging approach has to facilitate a few important conditions for single-mode short pulse operations and nearly thermally independent lasing, the most important one being its ability to exclude any multi-mode and/or mixed mode operations. The temperature elevations within the laser cavity and thermal stresses in micro-chip laser often affect multi-mode and/or mixed mode operations. In some of those single mode operations, the wavelength has to be tunable, in order to permit wavelength or phase locking. These packaging approaches are essential for novel tactical laser transmitters, LADAR, and space sensor systems, and low mass proximity fuses.
Prior attempts have featured laser components coupled with commercial thermal management devices having relatively large size and poor utility for commercial and military applications. This strongly drives the need for miniaturized electro-optical laser systems and packaging designs. These designs should provide low component stresses in all the enclosure units that can be combined with low absorption of light.